Automatic grinding device



June 27, 1939. LE 2,164,155

vAUTOMATIC GRINDING DEVICE Filed Dec. 22, 1938 ATTORNEYS VENTOR Patented June 27, 1939 UNITED STATES PATENT OFFICE My present invention relates to lens grinding machines and more particularly to an attachment for existing'machines to enable the elimination of waste motion in such machines thus 5 speeding up the grinding process.

In the accompanying specification I shall describe, and in the annexed drawing show, an illustrative embodiment of the present invention. It is however to be clearly understood that the present invention is not limited to the exact details of construction herein shown and described for purposes of illustration only inasmuch as changes therein may he made within the scope of the claims hereto appended without the exercise of invention.

In the accompanying drawing,

Fig. l is a plan View of a lens grinding machine provided with an attachment constituting the aforesaid illustrative embodiment of the present invention.

Fig. '2 is an enlarged side view looking line 2-2 of Fig. l, and

Fig. 3 is a similar view looking along line tt of Fig. l; 25 Before describing my invention in detail,. I deem it advisable briefly to refer to the prior art in the field to which thepresent invention relates and to point outthe disadvantages thereof, and the manner in which the present invention overcomes the same In the existing lens grinding machines, thelens to be ground is continually rotated at a slow rate of speed. Obviously, some portions of the lens become finished before others due to many reasons. For one thing, lenses are not generally of auniform thickness throughout so that the thin portions are easier to grind than those which are thicker, the thin portions thus becoming finished first. However,, in the existing 0 machinesfin view of .the continuous rotation of V the lens, there are times when the machine is operating but no grinding is being done and no I grinding can be done until another high spot or along I unground portion of the lens is presented to the I grinding wheel. .This waste motion needlessly extends the time necessary to complete, the rindin i J By means of the present invention, I am able to slightly alter the'existing, machines so as to have the lens rotate only when grinding at. any

ticallycontinuous grinding of the lens thus eliminating waste motion and considerably shortening the time necessary to finish the grinding. As a matter of fact, I have found that the grinding time is reduced to one-quarter of that necessary with existing machines.

Other objects and advantages of the present invention will readily occur to those skilled in the art as the detailed description progresses.

Referring now more in detail to the aforesaid illustrative embodiment of the present inven- 7 ing wheel it which in addition to being rotatable is given a reciprocating side-to-side motion.

The latter is accomplished through the following means: J

The shaft l is provided with a pulley it over which is trained an endless belt l2, one end of which engages another pulley l3, which, through the worm It, worm wheel l5 and arms it impart a reciprocating motion to the shaft i.

All of this construction is conventional and constitutes no part of the present invention. The other end of the looped belt i2 is trained over a pulley I'I fixed upon a shaft ill the inner end of which is engaged by a fork l9 attached to the armature 20 of 7 an electroemagnet 2i.

The shaft I8 is not only rotatably mounted in the frame 6 but it is in addition, slidable therein. On the outer end of the shaft I8 is a pinion 22 adapted, when the shaft I8 is moved outwardly through the action of the electro-magnet 2|, to engage-a gear 23 fixed upon a shaft 24 rotatably mountedin the frame 6. The pinion 22 constitutes a clutch. The inner end of the shaft 24 is provided with a pinion 25 in mesh with a gear 26 fixed upon a shaft. 21 journallecl in the frame 6. Opposed to the shaft 21 is another shaft 28, likewise journalled in the frame 6 and having fixed on the outer end thereof a gear 29 in mesh with a'pinion. 30. The latter may either be fixed upon a separate stub shaft or it may be fixed upon a continuation of the shaft 2 which carries the pinion 25.

' The facing ends of the shafts 21 and 28 are provided with jaws 3| of a vise adapted to clamp therebetween the piece of glass 32 or unground blank which it is desired to shape into a lens and a pattern wheel 33 which is adapted to determine the size and shape of the lens. The latteris made of metal and is adapted, as will hereinafter be more fully explained, to complete a certain electrical circuit so as to operate the electro-magnet 2| and thus controlthe rotation of the lens 32.

Fixed to the frame 6, and'insulated therefrom is a contact plate 34 connected by a wire 35 to one end of the electro-magnet 2|. The other end of the electro-magnet is connected by a. wire 36 to a source of electrical current 31 and the other end of the source of current is grounded by a wire 38 to the frame 6 of the machine. Inasmuch as the pattern wheel, 33 is likewise ounded to the frame 6 the electrical circuit through the electro-magnet 2| can only be completed when the pattern 33 engages the contact plate 34.

The device is completed by providing a pawl 33 in contact with the gear 33, the purpose of which is to provide an audible signal continually in operation when the grinding has been completed.

This completes the description of the aforesaid illustrative embodiment of the device of the present invention and its mode of use may be briefly summarized as follows:

Normally, no current is flowing through the.

electro-magnet 2| so that the pinion or clutch 22 is not engaged with the gear 23. Thus, although the pinion 22 is continually rotating, the gear 23 and the. train driven thereby, including the lens 32, is not rotating.

When it is desired to grind the lens, an unground blank comprising a piece of glass roughly having the shape of the finished lens is clamped between the jaws 3| together with a pattern 33 of the desired size and shape. By any preferred means, such as a tension spring 40 the periphery of the lens is maintained in contact with the rotating grinding wheel It. At this time, the pattern 33 is not in contact with the plate 24. Thus, the portion of the lens presented to the wheel III is ground but the lens remains stationary. As the grinding continues, the lens moves closer to the wheel Ill under the tension of the spring 43 and when a sufllcient amountof the glass has been ground away the pattern 33 comes into contact with the plate 34 and the electrical circuit through the electro-magnet is completed. Thus the pinion 22 is shifted into mesh' with the gear 23 to permit rotation of the latter and the train and lens geared thereto. This rotation continues only until a high spot or unground portion of the lens contacts the wheel II; for, at this time, the pattern 33 will be moved away from the plate 34 to break the electrical circuit'through the electro-magnet, which per- -mits the armature 20 to return to its normal position, disengaging the pinion 22 from the gear 23. The portion of the lens 32 then being presented to the grinding wheel III will be ground until, again, a sufllcient amount thereof has been ground away to permit contact between the pattern 33 and plate 34. .The device will then operate as before described. This intermittent grinding and rotation will continue until the lens has been ground away sufilciently to permit continuous contact between the pattern 33 and Plate 34.

.This results in a continuous circuit through the electro-magnet 2| and this causes continued rotation of the gear 23 and the lens 32. The continuous sound of the teeth of the gear 23 moving over the pawl 39 will advise the operator that the grinding is completed.

This completes the description of the mode of use of the device of the present invention and it will be noted from all of the foregoing that the device is simple inconstruction, easy and economical to fabricate and assemble and is admirably adapted to perform the intended functions.

Other objects and advantages of the present invention will be obvious to those skilled in the art to which the present invention relates.

What I claim as my invention is:

1. In combination with a lens grinding machine having a constantly rotating grinding wheel, a clamping device receptive of an unground blank and adapted to expose a portion thereof to the action of the grinding wheel, means operable upon the completion of the grinding of the exposed portion of the blank, to automatically move the same to expose another unground portion thereof, electro-magnetic means to control said last named means, and a pattern associated with said blank to complete an electrical circuit through said electro-magnetic means at predetermined intervals.

2: In combination with a lens grinding machine having a constantly rotating grinding wheel, a clamping device receptive of an unground blank and adapted to expose a portion thereof to the action of the grinding wheel, and means operable upon the completion of the grinding of the exposed portion of the blank, to automatically move the same to expose another unground portion thereof, said means including a train of gears to rotate said clamping device, electro-magnetic means to control said train of gears, and a pattern associated with said blank to complete an electrical circuit through said electro-magnetic means at predetermined intervals.

3. In combination with a lens grinding machine having a constantly rotating grinding wheel, a clamping device receptive of an unground blank and adapted to expose a portion thereof to the action of the grinding wheel, and means operable upon the completion of the grinding of the exposed portionof the blank, to automatically move the same to expose another unground portion thereof, said means including means to rotate said clamping device, a clutch engageable with the last named means, electromagnetic means to control .said clutch, and a pattern associated with said blank to complete an electrical circuit through said electro-magnetic means at predetermined intervals.

4. In combination with a lens grinding machine having a constantly rotating grinding wheel, a clamping device receptive of an unground blank and adapted to expose a portion thereof to the action of the grinding wheel, and means operable upon the completion of the grinding of the'exposed portion of the blank, to automaticaly move the same to expose another unground portion thereof, said means including a train of gears to rotate said clamping device, a clutch engageable with said train of gears, electro-magnetic means to control said clutch, and a pattern associated with said blank to complete an electrical circuit through saidelectro-magnetic means at predetermined intervals.

5. In combination with a lens grinding machine having a constantly rotating grinding wheel, a clamping device receptive of an unground blank the same to expose another unground portion and adapted to expose a portion thereof to the action oi the grinding wheel, and means operable upon the completion of the grinding of the exposed portion of the blank, to automatically move thereof, said means includingmeans to rotate said clamping device, electro-magnetic means to control said last named means, an ope'nelectrical circuit through said electro-magnetic means, said circuit including a contact plate, and a pattern associated with said blank engageable with said contact plate at predetermined "intervals to complete said electrical circuit.

ii. In combination with a lens grinding machinehaving a constantly rotating grinding wheel, a I clamping device receptive of an unground blank and adapted to expose a portion thereof to the action of the grinding wheel, and means, operable upon the completion of the grinding of the exposed portion of the blank, to automatically move the same to expose anotherunground portion thereof, said means including a train of gears to rotate said clamping device, electro-magnetic means to control said train oi gears, an open elec-' trical circuit through said electro-magnetic ,means, said circuit including a contact plate, and

pattern associated with said blank engageable with said contact plate at predetermined intervals to complete said electrical circuit,

7. In combination with a lens grinding machine having a constantly rotating grinding wheel, a clamping device receptive of an unground blank action of the grinding wheel, and means, operable upon the completion of the'grinding of the exposed portion of the blank, to automatically move the same to expose another unground portion thereof, said means including meansto rotate said clamping device, a clutch engageable with said last named means, electro-magnetlc means to control said clutch, anv open electrical circuit through said electro-rnagnetic means, said circuit including a contact plate, and avpattern associated with said blank engageable with sai'd contact plate at predetermined intervals to complete said electrical circuit. I

8. In combination with a lens grinding machin having a constantly rotating grinding wheel, a

clamping device receptive of an unground blank and adapted to expose a portion thereof to the action oi. the grinding wheel, and means, operable upon the completion of the grinding of the exposed portion of the blank, to automatically move the same to expose another unground portion thereof, said means including a train of gears to rotate said clamping device, a. clutch engageable with said train of gears, electro-lnagnetic and adapted to expose a portion thereof to the 

